This invention relates in general to a sea anchoring system for anchoring a floating sea station to a fixed element in a sea bed such as a foundation or a stay.
Aside from prior art sea platforms which are supported by rigid towers anchored to the sea bed (see U.S. Pat. No. 3,522,709, for example), platforms or stations are known which are carried on submerged or semi-submersible floating bodies which are movably anchored to the sea bottom, as a rule through a plurality of hinged connecting arms which extend from the floating bodies in more or less inclined positions. These connecting arms must be relatively very stiff to withstand the forces which are produced by the swell of the sea and by which they are loaded particularly in bending and buckling. That is why these connecting arms are usually designed as heavy lattice girders resistant to bending and buckling (see German OS No. 24 607 89).
Recently, a novel anchoring system has been developed in which the submerged or semi-submerged floating body is held in place by means of tensile force transmitting members which are loaded in tension and secured to a foundation or stay block provided on the sea bottom (see for example, Ocean Industry, Feb. 1980 page 35 et seq.).
As a rule, the members transmitting the tensile forces are designed as tubular elements subjected to and withstanding only tension, wherefore they must be relieved from any bending forces. That is why in such anchoring systems, the ends of the members transmitting the tensile forces must be hinged to the floating bodies and to the foundation or stay blocks in a manner meeting this requirement. In addition, it must be taken into account in the design and construction, that an access to, or inspection of, such hinge points will be impossible, or extremely difficult after the anchoring is accomplished on the sea bottom, in a depth of 200 to 250 meters. A descent to such depths, even by specially trained divers, is hardly possible at the present time and, particularly, no maintenance or repair work can be considered. An inspection would be practical only upon towing the entire station ashore. It is well known what immense costs and difficulties this would involve.
Every care must therefore be taken in the design of such systems to ensure that the anchoring will remain in satisfactory condition for a long period of time, without disturbances and without maintenance.